Prices had been pegged very high due to the Ukraine famine in the 1920s, and global trade further collapsed due to Smoot Hawley ( which was immediately countered worldwide ). Redistributing excess produce for free can work well in the face of collapsing prices. It doesn't signal increased production and buffers people getting out of producing without completely destroying prices. Direct food subsidies continued well into the 1960 ( we called them "commodities", and if you were poor, you could get them from ... USDA offices? something like that). This was the predecessor to food stamps ( although it may have run in parallel ).